In situ Investigation of OH-Absorption in LiNbO3and LiNbO3:MgO Crystals during Reducing/Oxidizing Annealing

Sugak, Yu.; Sugak, D.; Zhydachevskii, Ya.; Solskii, I.; Buryy, Oleh; Ubizskii, S.; Becker, Klaus‐Dieter

doi:10.12693/aphyspola.117.170

Cited by 4 publications

(2 citation statements)

References 17 publications

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“…The results are in agreement with literature data, showing a broad absorption band centered at 3485 cm −1 with a full width at half maximum (FWHM) of ≈ 35 cm −1 for the as-grown sample. Its shape is slightly asymmetric with a shoulder at 3460 cm −1 as reported in references [32,33]. A qualitative similar spectrum with decreased OH −1 absorption amplitude is found in the reduction annealed sample in accordance with [10] for c-LT, but also for lithium niobate.…”

Section: Ground State Absorptionsupporting

confidence: 88%

Small electron polarons bound to interstitial tantalum defects in lithium tantalate

Pfannstiel,

Hehemann,

Schäfer

et al. 2024

J. Phys.: Condens. Matter

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The absorption features of optically generated, short-lived small bound electron polarons are inspected in congruent lithium tantalate, LiTaO3 (LT), in order to address the question whether it is possible to localize electrons at interstitial TaV:VLi defect pairs by strong, short-range electron-phonon coupling. Solid-state photoabsorption spectroscopy under light exposure and density functional theory are used for an experimental and theoretical access to the spectral features of small bound polaron states and to calculate the binding energies of the small bound TaLi 4+ (antisite) and TaV 4+ :VLi (interstitial site) electron polarons. As a result, two energetically well separated (ΔE ≈ 0.5 eV) absorption features with a distinct dependence on the probe light polarization and peaking at 1.6 eV and 2.1 eV are discovered. We contrast our results to the interpretation of a single small bound TaLi 4+ electron state with strong anisotropy of the lattice distortion and discuss the optical generation of interstitial TaV 4+ :VLi small polarons in the framework of optical gating of TaV 4+ :TaTa 4+ bipolarons. We can conclude that the appearance of carrier localization at TaV:VLi must be considered as additional intermediate state for the 3D hopping transport mechanisms at room temperature in addition to TaLi, as well, and, thus, impacts a variety of optical, photoelectrical and electrical applications of LT in nonlinear photonics. Furthermore, it is envisaged that LT represents a promising model system for the further examination of the small-polaron based photogalvanic effect in polar oxides with the unique feature of two, energetically well separated small polaron states.

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Section: Ground State Absorptionsupporting

confidence: 88%

Small electron polarons bound to interstitial tantalum defects in lithium tantalate

Pfannstiel,

Hehemann,

Schäfer

et al. 2024

J. Phys.: Condens. Matter

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“…It has generally been accepted that the 3484 cm −1 (2.87 μm) absorption band is intimately associated with the 0–1 stretching vibrational band of OH − molecular defects in LiNbO 3 . Furthermore, when the concentration of optical damage resistance impurities is above from a certain value then the IR absorption band shifts to larger energies (to shorter wavelengths) .…”

Section: Resultsmentioning

confidence: 99%

Modification of band gap in lithium niobate caused by indium incorporation

Castillo-Torres

2013

Physica Status Solidi (b)

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Phone: þ52 01 953 5320214, ext: 290, Fax: þ52 01 953 5320399Measurements on transition energies near the optical absorption band edge for lithium niobate samples doped with indium at several concentrations are presented. Indirect and direct optical absorption processes were analyzed. It was found that the energies for these transitions are larger than those corresponding to undoped lithium niobate, suggesting that the energy band structure was modified by the presence of indium. For an indium concentration between 0 and 4 mol%, a value of energy of 3.8 eV was measured for indirect transition, and a range of 3.9-4.0 eV was determined for direct transition energy; whereas 3.6 and 3.8 eV were obtained, respectively, for the corresponding values of pure lithium niobate. In addition, Urbach and phonon energies were also calculated for the same indium-doped lithium niobate samples which values are lesser than those obtained for pure lithium niobate. Both behaviors remain unaltered regardless of whether the indium concentration is above or below the optical damage threshold value. Substitution of only lithium vacancies and antisite defects by indium atoms for any concentration of doping may explain the results.

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